TECH Asteroids [yep, another one:-]

[adrian_cresswell]

[ukvac] TECH Asteroids [yep, another one:-]

As we seem to be in an Asteroids type mood..

I have three PCB's here, two of which just constantly light P1 & P2
buttons - nothing else - no test mode, no reset, no nothing [so to speak]

The third is perhaps the most promissing. When connected to the machine, you
can here the vector chatter, alternating as [I presume] it displays push
start - it's on free play - although the chatter is MUCH more pronounced
than on my working board - I haven't kept this on for more than a few
seconds btw! With the monitor disconnected [for monitor safety] the game
plays blind - no problem & makes the right noise in test mode.

On all three boards, I have verified [by substitution onto a working board]
that ROM's, CPU's and crystals are all fine.

The cab is fine too.

Any ideas would be much appreciated - unfortunately I do not have a scope,
but do have a logic probe, multimetere etc....

Thanks in advance

Adrian.

 

[guddler]

Re: [ukvac] TECH Asteroids [yep, another one:-]

Is the monitor known to work or is that in question too?

 

[adrian_cresswell]

RE: [ukvac] TECH Asteroids [yep, another one:-]

Sorry Martin, yes, the monitor is fine.

My Astreroids cab is 100% working. These are three additional boards that I
am trying to get going, using my working machine as a test bench

 

[eggwheatis]

RE: [ukvac] TECH Asteroids [yep, another one:-]

Sounds like you have no Z output from the board.

Phil.
--- Spadie <spadielists@btinternet.com> wrote:
> Sorry Martin, yes, the monitor is fine.
>
> My Astreroids cab is 100% working. These are three
> additional boards that I
> am trying to get going, using my working machine as
> a test bench
>

 

[guddler]

Re: [ukvac] TECH Asteroids [yep, another one:-]

Okay, i'm no expert yet as i still haven't got off my arse and looked at all the Asteroids / Delxue boards that i have and need fixing, but...

I would assume then that the spot killer is lighting?

If the deflection chatter is louder than when compared to your working board then that means the lines are being drawn considerably nearer the extremes of the tube, if not off the edge, so i guess you're right to turn the monitor off. Sounds like you knew this anyway!

If the spot killer IS on, then maybe only one of the axis is present? Randy Fromm has a section on XY game troubleshooting in his big blue book iirc which tells you the voltages you can expect to see on the X, Y & Z outputs with a DMM on a working board.

Peronally i'd stick this one back on the shelf and haver a go at the other two :O)

With the other two, it doesn't sound like the boards actually managing to run the code and you may find that fix that and they could have a perfectly good working vector section! Okay, unlikely, but you never know. I know you've already tried the roms and processor, so in this case it wasn't that, but my AD board (which is so far proving VERY reliable) came to me in that state and i was lucky enough to replace the cpu with a new one and have the board spring to life. Perfectly. Nice...

I'm sure others will be able to be more helpful, but if not i'll see what i can think of when i sit down to look at my boards which is looking more and more like it may become the next thing i look at.

Martin.

 

[eggwheatis]

Re: [ukvac] TECH Asteroids [yep, another one:-]

They just detect for X and Y deflection on all
monitors. There is a 90v spotkiller too on B/W
vectors.

Cheers, Phil.

--- Martin White <martin@guddler.co.uk> wrote:
> Related one then...
>
> Does the spot killer come on if there is no Z
> output? Generally, across the board, but if it's
> monitor specific, on the amplifone?
>
> Not according to the amplifone docs i was reading
> last night, but i think that could be wrong as this
> SW boardset looks good on a scope (without hooking
> up the Z axis), but on a known good deflection board
> the spot killer comes on!
>
> (Sorry to hijack the thread a little)
>

 

[Guests]

[ukvac] Re: TECH Asteroids [yep, another one:-]

If its doing excess chattering, its possible that the gain controls
are turned up way too high on the game board if its just
displaying "press start".

Are all the voltages ok on the regulator circuits for the d to a
sections ?

Regards, Colin

 

[guddler]

Re: [ukvac] TECH Asteroids [yep, another one:-]

Okay, thought as much!

Just trying to work out why a SW boardset that looks perfect on a scope would cause the spot killer to come on when using a known good deflection board.

I'll check the wiring harness and stuff first before going any further.

Martin.

 

[adrian_cresswell]

RE: [ukvac] TECH Asteroids [yep, another one:-]

Thanks Martin, Phil and Colin, for the suggestions with these three boards.

I think I'll take a quick look at the partially working one [no Z output]
then concentrate on the totally dead one's.

Thanks [as always]

Adrian.